These may eventually be classified as species or subspecies; Megalapteryx benhami (Archey) which is synonymised with M.
didinus (Owen) because the bones of both share all essential characters.
Moa fed on a range of plant species and plant parts, including fibrous twigs and leaves taken from low trees and shrubs. They are characterised by having low fecundity and a long maturation period, taking approximately ten years to reach adult size.
The beak of Pachyornis elephantopus was analogous to a pair of secateurs, and was able to clip the fibrous leaves of New Zealand flax (Phormium tenax) and twigs up to at least 8 mm in diameter. The large Dinornis species took the same length of time to reach adult size as small moa species, and as a result had an accelerated rate of skeletal growth during their juvenile years.
Their distributions in coastal areas have been rather unclear, but were present at least in several locations such as on Kaikoura, Otago Peninsula, Although the South Island and the North Island shared some moa species (Euryapteryx gravis, Anomalopteryx didiformis), most were exclusive to one island, reflecting divergence over several thousand years since lower sea level had resulted in a land bridge across Cook Strait.
Dinornis seems to have had the most pronounced sexual dimorphism, with females being up to 150% as tall and 280% as heavy as males—so much bigger that they were formerly classified as separate species until 2003.
The other moa species present in the North Island (Euryapteryx gravis, E.
curtus, and Pachyornis geranoides) tended to inhabit drier forest and shrubland habitats. geranoides occurred throughout the North Island, while the distributions of E. curtus were almost mutually exclusive, the former having only been found in coastal sites around the southern half of the North Island.
This would have allowed them to graze on low-elevation vegetation, while being able to lift their heads and browse trees when necessary.
This has resulted in a reconsideration of the height of larger moa.